Optical projection system

Claim 1

A PROJECTION SYSTEM COMPRISING THE COMBINATION, WITH AN ARC LAMP HAVING A PAIR OF OPPOSITELY EXTENDING ALINED ELECTRODES HAVING SPACED FACING ENDS ADAPTED TO FORM AN ARC AS A LIGHT SOURCE THEREBETWEEN, OF A HEMISPHERICAL RING MIRROR FORMED WITH A CENTRAL OPENING AND MOUNTED IN POSITION ENCIRCLING ONE END OF THE LAMP UP TO A PLANE THROUGH THE ARC AND NORMAL TO SAID ELECTRODES, SAID MIRROR BEING CONCENTRIC WITH RESPECT TO THE AXIS OF SAID ALINED ELECTRODES, A PRINCIPAL PROJECTION MIRROR OF CONCAVE CONFIGURATION AND FORMED WITH A CENTRAL OPENING, SAID PROJECTION MIRROR BEING SUPPORTED IN POSITION CONCENTRICALLY ENCIRCLING THE OTHER END OF THE LAMP UP TO THE EQUATORIAL PLANE OF SAID BULB, SAID PROJECTION MIRROR HAVING SPACED PARALLEL SIDES TRUNCATED ON PLANES EXTENDING ON OPPOSITE SIDES OF AND EQUALLY SPACED FROM THE ELECTRODE AXIS OF SAID LAMP, SAID PROJECTION MIRROR BEING POSITIONED TO RECEIVE LAMP EMITTED RAYS REFLECTED FROM THE RING MIRROR AS WELL AS DIRECTLY AND TO DELIVER SUCH RAYS THROUGH THE OPENING OF THE RING MIRROR AND UPON AN OBJECTIVE LENS DISPOSED OUTWARDLY OF THE LAMP AND IN LINE WITH ITS ELECTRODE AXIS, A PAIR OF DEFLECTING MIRRORS MUTUALLY INCLINED AND DISPOSED WITHIN THE RING MIRROR AND OUTWARDLY OF THE RING MIRROR ENCIRCLED END OF THE LAMP, AND A PAIR OF AUXILIARY PROJECTION MIRRORS DISPOSED OUTWARDLY OF THE TRUNCATED SIDES OF THE PRINCIPAL PROJECTION MIRROR IN POSITION EACH TO REFLECT LIGHT UPON A CORRESPONDING ONE OF SAID DEFLECTING MIRRORS AND THERE UPON THE OBKECTIVE LENS.